Emoia atrocostata, commonly known as the littoral whiptail-skink, mangrove skink, or littoral skink, is a species of lizard in the family Scincidae. It inhabits mangroves, back-beach vegetation and rocky shorelines. It is semi-aquatic and forages in tidal pools.

 The species can be distinguished from the similar many-lined sun skink by the lack of keeled scales on the dorsal surface of the Mangrove Skink. Its colour is grey or brown-grey, flecked with black. There is a faint black band along each side. The throat is often bluish, and the belly greenish or yellow to orange.

Distribution: E. atrocostata can be found on the Ryukyu Islands, Taiwan, the Philippines, Indonesia, Malaysia, Vietnam, Papua New Guinea, the Solomon Islands, Vanuatu and in Queensland, Australia.